1. Field of the Invention
This invention relates to chromatography, and more particularly concerns a new inlet seal assembly and method for use with gas chromatography instruments.
2. Description of the Prior Art
The prior art inlet seal member which is used to make a leak free seal between an injection port member of a split/splitless injector and a reducing nut is made from stainless steel and may be coated with some material, i.e., gold, silver, etc. The seal is made by placing an inlet seal member in a reducing nut which has female threads that thread into male threads on the outer surface of the injection port member. The bottom surface of the injection port member has a small raised circular sealing ring of metal, and the seal is made by tightening the reducing nut which holds the inlet seal member to cause the raised circular sealing ring on the injection port member to cut into the top surface of the inlet seal member and make a metal to metal seal.
This prior art arrangement has a number of problems. For example, excessive torque must be used to achieve a leak free seal between the top surface of the inlet seal member and the sealing ring. Also, the injection port member and the inlet seal member must be machined to tight tolerances to insure squareness on both the injection port circular sealing ring and the inlet seal member upper surface or the integrity of the seal is compromised.
Also, the injection port circular sealing ring may become scratched, dented, or otherwise damaged and this compromises the seal.